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I am getting ready to install a Weil-Mclain Ultra in my 4 family apartment buliding. It stesses how important it is to flush any sediment out of the lines. Here is where my problem comes in. The system was once a gravity feed system (building was built in 1939) most lines are 3" and I have drained the whole system and was really suprised at the amount of water it held. I don't think by just running water through it will be enough to dislodge any sediment as it will have to fill all the lower lines till it reaches the top and comes back down. Should I just fill er' up and hope for the best? I guess I will dismatle the heat exchanger and try to remove any deposits in the spring. If any body has any ideas please let me know.

more problems

I added the strainer. Everything was up and running. At first I noticed the firing would drop around 100 then go to 70 and up to a hundred, but never hit the target temp of 140. I thought it was just part of the efficent cooling deal. But after about 30 min. the boiler stopped and the display showed as if the call for heat had been satisfied. I went through all the wiring, checked the fuses (even replaced them for good measure). No errors are present on the display. Here is where things get aggravating. I can jump the terminals for the water heater and everything works as it should, but nothing on the boiler side. Could this possiably be in the board? or am I over looking somthing obvious?

I tried it without temp sender and still nothing. I really think it might be somthing in the board. It just don't make much sense that no fault shows or no error code is given and it works like a champ on the DWH side. The temp on display was correct for what was going on outside.

It seems that you need to understand how the boiler works.This boiler will modulate & decrease the input according to supply & return temps.If there is a light load the return temp will reach temps near to supply temp & the firing rate will reduce.Also with outdoor reset it will reduce target temp automatically.The target temp should increase for domestic on a call for dhw.I think the factory temp was 190deg.?You do have to set the board up to run dhw.Call someone out familiar with the boiler setup & pay them to set it up.WeilMcLain does have alot of info available online too.

Mark, the outdoor sending unit was set up, which changes the factory temps. Even on inital fire-up it never reached the target temp (140)before shutting off. I do understand how the boiler works ( thats why I paid so much for it) I don't have it set for DHW, I just jumped the two terminals to see if it would fire (Per the trouble shooting guide.). The only open remedy is to replace the board. Just to check with what you are saying I will flip it on this morning to check it out. But I went through the manual page by page, which is the same one avaliable at W-M. If I turn it on and it works fine I will come back and admit to being a bone-head.

Well, I went back this morning and flipped it on. Nothing! So I call the I called the allmighty tech guy in PA and as soon as he mentioned setting the parameters I had a felling right away that was the problem. I had the space heat turned off in the parameter section. Apparently once all the hard work of getting it set up and running and seeing all the options and functions of this awsome boiler (my hands were pushing buttons like a kid in a candy store) I musta somehow switched the 1 to a 0. Oh well it is running now. The tennants are happy. They might even pay the rent next month, but I wont get my hopes up. Thanks for the suggestion of strainers- The guy at the parts counter had to think for a minute about what they were, guess not a much ask for part.